17th May Learning Summary of Variance and Standard Deviation

First set of numbers :-10,0,10,20,30

Second set of numbers:8,9,10,11,12

So the mean for both of them are 10

But the variance for the first one is (-10-10)2+(0-10)2+(10-10)2+(20-10)2+(30-10)2/5=200

The second one is (8-10)2+(9-10)2+(10-10)2+(11-10)2+(12-10)2/5=20

then the standard deviation equals square root of variance

square root of 200 = 10 2

square root of 20 = 2

which means the first one is more dispersed than the second one, the gap between each numbers is 10 times more than the second.

Now you got the idea what the variance and standard deviation is, Tiger : )